1. Field of the Invention
The present invention relates to a hull provided with reaction flaps to impart lateral stability at high speeds.
2. Description of the Prior Art
Transom types of high-speed ships having a single hull in the prior art include a chine type of high-speed ship and a round bilge type of high-speed ship. The former type of high-speed ship is shown in FIGS. 15 to 17, and the latter type of high-speed ship is shown in FIGS. 18 to 19.
In these respective figures, reference numeral 1 designates the waterline, numeral 2 designates a wave washing up along a surface of the hull of the ship or spray from the bow during navigation, numeral 3 designates a wave at the transom of the ship, numeral 4 designates the direction of travel of the ship, numeral 5 designates an upper deck of the ship, numeral 6 designates a bottom keel of the ship, numeral 7 designates a chine, and numeral 8 designates a round bilge.
In the heretofore known single-hull transom types of high-speed ships, it was a common practice to employ a chine to form a squarish bilge as shown in FIGS. 15, 16 and 17 or to employ a slender hull having a large length-to-width ratio as shown in FIGS. 18, 19 and 20 for preventing waves from washing up along a surface of the hull or spray 2 from arising from the bow during high-speed navigation. It was also common practice to employ a small reaction flap, that is, a spray strip, for suppressing the spray 2.
It is well known that it is difficult for some types of ships to exceed a certain speed by merely increasing power. Rather, to achieve such a high speed it is necessary to reduce the tendency of the ship to produce outward spray. In general, a ship having a transom and exhibiting a smooth sliding performance at high speeds is to be considered.
In this regard, a large length-to-width ratio might inhibit the production of spray or waves. However, in this case, if the length-to-width ratio exceeds a certain fixed value, then the ship loses lateral stability. That is, the ship will heel too readily. Moreover, directional stability is also lost, and safe high-speed navigation becomes impossible.
Even if a ship has a sufficient stability when stationary, unless it has a sufficiently high stability, it will nonetheless become increasingly unstable at high speeds. This condition has been confirmed to a certain extent as a result of research in recent years.
In summary, if a ship of the heretofore known type were to have a length-to-width ratio smaller than a certain value and a stability, while stationary, that is not sufficiently large, such a ship would become laterally unstable at a certain high speed.